Restoring Taylor 22 signal tracer - UK Vintage Radio Repair and Restoration Discussion Forum

Mike Phelan · 27th Jun 2007, 4:47 pm

As in this thread here, I have acquired one of these items from Testgear John, in mint condition except for the escutcheon being damaged by solvent – see pic.

As most of the work has been doing this, I have put a second post in to show what was done; I did not make it a separate thread as some of it is specific to this item.

Apart from that, all that was needed was a quick clean of the rotary switch, pot and valve bases. Yes – I saw the Hunts capacitor, but it measures fine, and the HT voltage is quite low. Circuit diagram and parts list are on this thread. Checked all the high value resistors, and they were fine as well; the EM81 lights the room up!
Thank you, John – it will get well used!

Mike Phelan · 27th Jun 2007, 4:49 pm

This is thin alloy with light grey writing on a black background which was probably screen-printed. Some of the black had been removed, possibly by an encounter with a solvent.
The grey is some sort of anodising on the metal panel, which you could see on the back of it.
The first job was to remove the panel (knobs, nuts on terminals and the top corners used those expanding plastic rivets that needed the centres pushing out from the inside)

One of the grub screws on the knobs would not budge. I usually find that the following method works if the screw is not damaged.
Soak the screw in penetrating oil (white spirit and oil mix) for a day, then heat the screw with a soldering iron. Using a good screwdriver, tap it with a small hemmer to loosen the bond. Try turning it the opposite way, then try to remove it, using pliers on the driver while you hold it into the slot with some pressure. Few will resist then!

I scanned the panel, using the highest resolution, and proceeded to refurbish the graphic. I won’t go into too many details, as it would be worth a separate thread, and there are those who are much better at this sort of thing than I am. A few comments, though, for this panel as well as a few generalities.

Use the maximum scan resolution and put a ruler in with it. I then use Paintshop Pro to change the file type and colours needed, crop it, and then use Paint for the rest of the process.
Convert it to a bitmap – this is the purest file type with no compression at all. Use 16 colours, not black-and-white as you can put layout lines in, say, red, and then flood-fill them in black when done.
Set the colour to white-on-black, and delete all the bits of foreground except the writing that should be black.
Copy each part of the panel (words, logo, calibrations) into a working area outside the panel while you replace it.
The nearest font was Arial, but there were a few differences:
E, F, T and L were narrower – I cut the ends off. D, B, P and R were as well so I “squashed them up” Spacing between letters was greater – no problem. Letter “M” had sloping sides – I had to make that. Zero and one were “O” and “I”, not “0” and “1”. So, all the writing was done.

The logo was very bad – I scanned the green-and-yellow one on the manual, changed and resized it.
For the calibrations that consisted of a circle with radial graduations, I drew a couple of horizontal layout lines top and bottom of the original and made a new circle and lines.
Each of these items in the working area, I went to the panel, put little lines to show the position, and deleted the original. The replacements then went in; a final deletion of any poor black bits, and the job was done. As a final job, the black edges were made wider so they extended outside the metal panel.

I printed it on cheap paper so I could get it the exact size – that is easy to do in Word or PSP. That is why I scanned the ruler.
I used a clear waterslide transfer so the writing was transparent and the metal showed through the writing. I cleaned the remains of the printing off the panel first – not difficult.
Despite the fact that I used a B&W laser printer and used inkjet transfer media, it was fine. After letting the transfer dry, I used a rat-tail file on the edge and all the holes to carefully remove overlapping parts of the transfer. A final spray with lacquer, and the job was complete.

Testgear John · 28th Jun 2007, 7:57 pm

That's great, Mike, I'm glad it found a good home! Both this, and the 44 were part of an ebay purchase, £100 the lot, I still have the unused Taylor 45D valve tester, now pristine with the replacement of the "A" pot 2k wirewound lin. It's in such good nick, and with the recent purchase of near mint manual and valve tables, (Crowthorne Tubes, thanks, Gerry) I'm very pleased with the purchase!

John.

Alf Fisher · 29th Jun 2007, 7:49 am

Brilliant job Mike. You said the HT was quite low but please could you measure the transformer HT secondary voltage for me. Ta.
Alf

Mike Phelan · 29th Jun 2007, 7:59 am

Here we are, Alf - HT at rectifier is 160v. The first two stages are run under starvation conditions, so, with switch set at RF:

V1 - anode 20, g2 22
V2a - anode 15, cathode 0.6
V2b - anode 125, cathode 7.5
V3 - anode 155, target 160.

HTH

PS - are you making one?

Alf Fisher · 1st Jul 2007, 8:39 am

Mike,
Those voltages are very low arent they. I expect the rectifier is not very efficient which is what prompted me to ask what the HT secondary volts were. But thinking more about it, what you need is to end up with 160v HT rail on the magic eye target. I assume that all the power supply components are built inside the base of the case. It looks to be a very useful piece of kit and its certainly on my wish list if I dont manage to find one somewhere. If I did make one it would probably be functionally the same but not be in a multimeter case unless I found a redundant Bradley CT471 or similar.

Alf

Mike Phelan · 1st Jul 2007, 5:43 pm

True, Alf, but the mains transformer is quite small, and as you say, there is no high HT needed for anything.
It does not need a fantastic gain either.
It is only the transformer, voltage selector and fuse that are mounted in the case - the triple electrolytic is on the chassis as shown and the 10k and 2k2 1 watt resistors are mounted across the tags of the can.
The rectifier is one of those potted in a rectangular can and screwed to the top of the chassis - invisible in the picture as the smoothing can hides it.

I have been looking for one for years now until I found this, and was going to make one until this one turned up.

Would be an interesting and useful project. Yeah - you could use an LM380 and OA47, but it would have no soul in it.

27th Jun 2007, 4:47 pm	#1
Mike Phelan Dekatron Join Date: Nov 2003 Location: Near Leeds, West Yorkshire, UK Posts: 4,609	Restoring Taylor 22 signal tracer As in this thread here, I have acquired one of these items from Testgear John, in mint condition except for the escutcheon being damaged by solvent – see pic. As most of the work has been doing this, I have put a second post in to show what was done; I did not make it a separate thread as some of it is specific to this item. Apart from that, all that was needed was a quick clean of the rotary switch, pot and valve bases. Yes – I saw the Hunts capacitor, but it measures fine, and the HT voltage is quite low. Circuit diagram and parts list are on this thread. Checked all the high value resistors, and they were fine as well; the EM81 lights the room up! Thank you, John – it will get well used! Attached Thumbnails __________________ Mike. Last edited by Mike Phelan; 28th Nov 2009 at 4:53 pm. Reason: Typo spotted two years later!

27th Jun 2007, 4:49 pm	#2
Mike Phelan Dekatron Join Date: Nov 2003 Location: Near Leeds, West Yorkshire, UK Posts: 4,609	Restoring Taylor 22 signal tracer panel This is thin alloy with light grey writing on a black background which was probably screen-printed. Some of the black had been removed, possibly by an encounter with a solvent. The grey is some sort of anodising on the metal panel, which you could see on the back of it. The first job was to remove the panel (knobs, nuts on terminals and the top corners used those expanding plastic rivets that needed the centres pushing out from the inside) One of the grub screws on the knobs would not budge. I usually find that the following method works if the screw is not damaged. Soak the screw in penetrating oil (white spirit and oil mix) for a day, then heat the screw with a soldering iron. Using a good screwdriver, tap it with a small hemmer to loosen the bond. Try turning it the opposite way, then try to remove it, using pliers on the driver while you hold it into the slot with some pressure. Few will resist then! I scanned the panel, using the highest resolution, and proceeded to refurbish the graphic. I won’t go into too many details, as it would be worth a separate thread, and there are those who are much better at this sort of thing than I am. A few comments, though, for this panel as well as a few generalities. Use the maximum scan resolution and put a ruler in with it. I then use Paintshop Pro to change the file type and colours needed, crop it, and then use Paint for the rest of the process. Convert it to a bitmap – this is the purest file type with no compression at all. Use 16 colours, not black-and-white as you can put layout lines in, say, red, and then flood-fill them in black when done. Set the colour to white-on-black, and delete all the bits of foreground except the writing that should be black. Copy each part of the panel (words, logo, calibrations) into a working area outside the panel while you replace it. The nearest font was Arial, but there were a few differences: E, F, T and L were narrower – I cut the ends off. D, B, P and R were as well so I “squashed them up” Spacing between letters was greater – no problem. Letter “M” had sloping sides – I had to make that. Zero and one were “O” and “I”, not “0” and “1”. So, all the writing was done. The logo was very bad – I scanned the green-and-yellow one on the manual, changed and resized it. For the calibrations that consisted of a circle with radial graduations, I drew a couple of horizontal layout lines top and bottom of the original and made a new circle and lines. Each of these items in the working area, I went to the panel, put little lines to show the position, and deleted the original. The replacements then went in; a final deletion of any poor black bits, and the job was done. As a final job, the black edges were made wider so they extended outside the metal panel. I printed it on cheap paper so I could get it the exact size – that is easy to do in Word or PSP. That is why I scanned the ruler. I used a clear waterslide transfer so the writing was transparent and the metal showed through the writing. I cleaned the remains of the printing off the panel first – not difficult. Despite the fact that I used a B&W laser printer and used inkjet transfer media, it was fine. After letting the transfer dry, I used a rat-tail file on the edge and all the holes to carefully remove overlapping parts of the transfer. A final spray with lacquer, and the job was complete. Attached Thumbnails __________________ Mike.

28th Jun 2007, 7:57 pm	#3
Testgear John Tetrode Join Date: Apr 2006 Location: Larne, Northern Ireland, UK. Posts: 64	Re: Restoring Taylor 22 signal tracer That's great, Mike, I'm glad it found a good home! Both this, and the 44 were part of an ebay purchase, £100 the lot, I still have the unused Taylor 45D valve tester, now pristine with the replacement of the "A" pot 2k wirewound lin. It's in such good nick, and with the recent purchase of near mint manual and valve tables, (Crowthorne Tubes, thanks, Gerry) I'm very pleased with the purchase! John.

29th Jun 2007, 7:49 am	#4
Alf Fisher Hexode Join Date: Sep 2005 Location: Potton, Bedfordshire, UK. Posts: 293	Re: Restoring Taylor 22 signal tracer Brilliant job Mike. You said the HT was quite low but please could you measure the transformer HT secondary voltage for me. Ta. Alf

29th Jun 2007, 7:59 am	#5
Mike Phelan Dekatron Join Date: Nov 2003 Location: Near Leeds, West Yorkshire, UK Posts: 4,609	Re: Restoring Taylor 22 signal tracer Here we are, Alf - HT at rectifier is 160v. The first two stages are run under starvation conditions, so, with switch set at RF: V1 - anode 20, g2 22 V2a - anode 15, cathode 0.6 V2b - anode 125, cathode 7.5 V3 - anode 155, target 160. HTH PS - are you making one? __________________ Mike.

1st Jul 2007, 8:39 am	#6
Alf Fisher Hexode Join Date: Sep 2005 Location: Potton, Bedfordshire, UK. Posts: 293	Re: Restoring Taylor 22 signal tracer Mike, Those voltages are very low arent they. I expect the rectifier is not very efficient which is what prompted me to ask what the HT secondary volts were. But thinking more about it, what you need is to end up with 160v HT rail on the magic eye target. I assume that all the power supply components are built inside the base of the case. It looks to be a very useful piece of kit and its certainly on my wish list if I dont manage to find one somewhere. If I did make one it would probably be functionally the same but not be in a multimeter case unless I found a redundant Bradley CT471 or similar. Alf Last edited by Alf Fisher; 1st Jul 2007 at 8:51 am.

1st Jul 2007, 5:43 pm	#7
Mike Phelan Dekatron Join Date: Nov 2003 Location: Near Leeds, West Yorkshire, UK Posts: 4,609	Re: Restoring Taylor 22 signal tracer True, Alf, but the mains transformer is quite small, and as you say, there is no high HT needed for anything. It does not need a fantastic gain either. It is only the transformer, voltage selector and fuse that are mounted in the case - the triple electrolytic is on the chassis as shown and the 10k and 2k2 1 watt resistors are mounted across the tags of the can. The rectifier is one of those potted in a rectangular can and screwed to the top of the chassis - invisible in the picture as the smoothing can hides it. I have been looking for one for years now until I found this, and was going to make one until this one turned up. Would be an interesting and useful project. Yeah - you could use an LM380 and OA47, but it would have no soul in it. __________________ Mike.